<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>行高</title>
  <style>
    div{
      width: 120px;
      height: 48px;
      color:#fff;
      font-size: 17px;
      font-family: Arial,sans-serif;;
      background-color: #4E6EF2;

      text-align: center;
      /* 
        使用行高技巧: 实现文字垂直居中
        操作方式: 行高等于容器高度
      */
      line-height: 48px;
    }

    div:hover{
      background-color: #4662D9;
    }
  </style>
</head>
<body>
    <div>百度一下</div>

    <input type="button" value="百度一下">
</body>
</html>